42179 Planet Earth and Moon in Orbit

[ReplicaOfLife]

Reminds me a lot of the MOC by JKBrickworks:

https://jkbrickworks.com/earth-moon-and-sun-orrery/

 

[gyenesvi]

1 hour ago, icm said:

However, it doesn't look like they managed to make the Earth spin as it goes around the Sun.

What do you mean? There's a U-joint going into Earth from underneath, that's for spinning it.

[icm]

Sorry, I didn't look that closely.

[allanp]

10 hours ago, Davidz90 said:

So excited for this set!

IMO the orange rings would look better in gold (and the month names would be more readable as well).

Agreed, the red rings would be better in gold, and the blue gear and pins really stand out here in a set where the mechanics are meant to be more visible. I wonder if a black 20t double bevel can be used instead? The other seemingly random blue and white parts are also distracting. But that's really my only real complaint, they can be swapped out for more tasteful colours, otherwise it looks fantastic. 

Edited December 1, 2023 by allanp

[R0Sch]

Imho it looks like a mess of liftarms, gears and colorful pins & axles. The lazy molds for hemispheres, the ugly robotic wheels as feet and the lack of attachments for a motor just doesn't confer it a premium product vibe. I have the CaDA version and that one is so much better, clean and elegant looking and it cost me half of this LEGO version. And they only did it because it was popular on Ideas and the competition released a similar tellurion.

[howitzer]

51 minutes ago, R0Sch said:

Imho it looks like a mess of liftarms, gears and colorful pins & axles. The lazy molds for hemispheres, the ugly robotic wheels as feet and the lack of attachments for a motor just doesn't confer it a premium product vibe. I have the CaDA version and that one is so much better, clean and elegant looking and it cost me half of this LEGO version. And they only did it because it was popular on Ideas and the competition released a similar tellurion.

While I'm really happy that they released this kind of thing and I'm going to buy it, I can't help but to agree with you in there that it has shortcomings. I don't mind the two-hemisphere earth and sun, those are completely fine (as opposed to brick-built spheres, which tend to be just ugly) but when I heard about the upcoming release of an orrery, I really hoped there would be proper covering in the stand and arm, as there was in the Ideas submission, which was gorgeous. There also doesn't seem to be obvious motorization option, which really should be included in a set like this. On the other hand, it's nice to see what all those gears actually do, like was in the olden days when vehicles had open frames, so it's not all bad I guess.

All of those shortcomings can of course be fixed on our own, but still my expectations were higher than this.

 

Edited December 1, 2023 by howitzer

[HydroWorld Outlook]

That's true. But I'm very happy to see that we're finally getting those Technic ring elements (which were previously only found in LEGO City and Friends sets) in more useful colors with this set. Also, I'm curious to see if there are other applications for the new large Technic hemispheres in this set. If TLG releases them in clear in some point, we could create Gyrospheres with them. Or they could be used as wheels, or maybe even airtanks or floatation devices if the two halves are sealed up with tape (the latter two ideas would be more difficult to execute, but I'm very curious to see if any MOC builders would choose to use them for those purposes).

Either way, without a doubt, this set's a sure buy for me.

Edited December 2, 2023 by HydroWorld Outlook

[aeh5040]

This looks fantastic to me. I like the exposed gears etc. I never thought they would release a set like this.

Hopefully they will sell a lot at museums etc. besides the usual channels. Then perhaps we can hope to see more "pure mechanism" type sets.

[EWay]

On 12/1/2023 at 5:15 PM, icm said:

This looks very good. It's probably going to be the one Technic set I buy this year - I probably can't afford the big crewed Mars rover. I'm impressed by the printing on the Earth globe and I'm glad they tilted the axis of the Earth. However, it doesn't look like they managed to make the Earth spin as it goes around the Sun. I wonder how close the gear ratio between the movement of the Earth around the Sun and the movement of the Moon around the Earth is to the authentic 365/28 ~ 13:1 ratio?

Allow me to interject with a bit of astronomical education... there are two ways to measure a lunar month (well actually there are more but two relevant here). There's a synodic month, which is the lunar month as observed from earth, and there's the sidereel month, which is the lunar month as observed from a fixed point in space. A synodic month is 29 days and 12 hours, and it's 2 days longer than a sidereel month because after a month of looking up at the moon, you've moved 1/12th of the way around the sun, so the moon has had further to travel to appear to get to the same angle in the sky. So I think a 12:1 ratio is closer than a 13:1 ratio in Lego, because any gearing that controls the moon is also moving around the sun, so it is essentially gearing from a frame of reference on the earth.

I expect we'll get a ratio of 360 earth rotations per "year" and 30 earth rotations per synodic month, because that's pretty easy to do with Lego gears. Hopefully the sun rotates as well, but that could be anything between every 24 and every 30 earth rotations, because the sun, being a fluid, doesn't rotate uniformly - it goes faster at the equator.

I've got some experience in this area... I'm going to jump on this bandwagon and post my orrery on here tomorrow :)

Edited December 5, 2023 by EWay
typo

[aeh5040]

I suspect the rotation speeds will be of the correct order but perhaps not really accurate. E.g. I would not be all that surprised if there were only 120 days in the year. Happy to be proved wrong of course.

The axis tilt is interesting too. Presumably it will retain its orientation during the Earth's orbit.

 

 

Edited December 6, 2023 by aeh5040

[howitzer]

6 hours ago, aeh5040 said:

I suspect the rotation speeds will be of the correct order but perhaps not really accurate. E.g. I would not be all that surprised if there were only 120 days in the year. Happy to be proved wrong of course.

The axis tilt is interesting too. Presumably it will retain its orientation during the Earth's orbit.

I really, really hope that they haven't designed this set with such enormous flaws, I mean 360 days in a year would be sufficiently close and not that hard to do, and as there's axial tilt of the Earth, I expect it to reflect the seasons correctly.

[R0Sch]

Probably the ugliest stand ever made in human history. Good thing they didn't pick the medium azure wheels to complete the rainbow.

[Jockos]

9 minutes ago, R0Sch said:

Probably the ugliest stand ever made in human history. Good thing they didn't pick the medium azure wheels to complete the rainbow.

Well, at least it has some useful parts, and finally these wheels in a Technic set. What I still don't understand is the use of the blue 3M beam...

[R0Sch]

1 minute ago, Jockos said:

What I still don't understand is the use of the blue 3M beam...

Just a dumb color coding for orientation during the build. Same with the axle and pin color. This is meant for new customers that never built a Technic set in their life.

[JaBaCaDaBra]

On 12/1/2023 at 8:27 PM, R0Sch said:

CaDA version and that one is so much better, clean and elegant.

You call that put together mess of studded bricks and plates elegant?

[R0Sch]

Oh, and there was a perfect sphere in the part list, that would have made a better looking sun, compared to these Bright Light Orange half spheres held together by yellow pins. Could have at least hidden the pins on the inside...
Studio file: 42179.io

Edited December 6, 2023 by R0Sch
added .io file link

[aeh5040]

On 12/1/2023 at 4:07 PM, msk6003 said:

Is this is new parts?

On backside of box, under the earth, you can find those circle thing. Size looks like 3x3 but it must have pin hole in middle for pass through drive axle of earth.

Like this but smooth outside and pin hole on middle.

I am not seeing anything that looks new here.  This looks like a LBG pin with stop bush going through a blue 3L liftarm up into a white 3L perpendicular connector.  Underneath some arrangement of pins and connectors (there are several possibilities) will connect that to the 28t turntable below, passing through the hole in the 60t turntable.

40 minutes ago, R0Sch said:

Oh, and there was a perfect sphere in the part list, that would have made a better looking sun, compared to these Bright Light Orange half spheres held together by yellow pins. Could have at least hidden the pins on the inside...
Studio file: 42179.io
 

There is second axle running along the bottom of the arm, which I think drives the 28t turntable in the Earth module, and is doubtless very important for the mechanics.  But where is it geared to in the Sun module?  It is at the level where two vertical 5x7 frames overlap, so there is not much room for gears.  Perhaps there is a 12t bevel (single or double) that meshes with the *underside* of the horizontal 20t double bevel?

Edited December 6, 2023 by aeh5040

[Davidz90]

17 hours ago, EWay said:

I expect we'll get a ratio of 360 earth rotations per "year" and 30 earth rotations per synodic month, because that's pretty easy to do with Lego gears. Hopefully the sun rotates as well, but that could be anything between every 24 and every 30 earth rotations, because the sun, being a fluid, doesn't rotate uniformly - it goes faster at the equator.

I also wonder if the proper 1:365 gear ratio will be used here, or some approximation. Since 365=5*73, one needs a little differential addition magic to obtain 1:73 gear ratio, but nothing too difficult, really.

and for a good measure, lunar month of 29.53125 days is also straightforward:

and very close to actual value of 29.53059 days

 

Edited December 6, 2023 by Davidz90

[aeh5040]

36 minutes ago, Davidz90 said:

I also wonder if the proper 1:365 gear ratio will be used here, or some approximation. Since 365=5*73, one needs a little differential addition magic to obtain 1:73 gear ratio, but nothing too difficult, really.

and for a good measure, lunar month of 29.53125 days is also straightforward:

and very close to actual value of 29.53059 days

Clever stuff.  I'm sure we won't get differential-drives this in the model, but it will be a nice challenge to fix it!

[R0Sch]

I just need to figure out a couple of things inside the main body, but the rest should be fine. Maybe in the meantime someone wants to calculate the gear ratios for the earth-moon system to see how accurate it is.

[aeh5040]

1 hour ago, R0Sch said:

I just need to figure out a couple of things inside the main body, but the rest should be fine. Maybe in the meantime someone wants to calculate the gear ratios for the earth-moon system to see how accurate it is.

Impressive work but I don't think this can be quite right. The Earth base with the tilt is not rotationally fixed to the Moon support - it needs to rotate independently. So its rotation needs to be powered by something. The only possibility I can see is that it is fixed to the top of the 28t turntable, presumably by two axles or pins running through the large turntable as I said above. So the tilt base and the small turntable top need to be rotationally aligned.

I agree that the top of the small turntable must be fixed to the bottom of the large one, as you seem to have. But so far as I can see, the pair of them cannot be fixed to the frame - they must be free to rotate, presumably with the red liftarm (or something attached to it) fitting snuggly inside the ring.

Unfortunately we can't compute anything unless we know how the lower axle is geared on the sun side, as I mentioned above.

Edited December 6, 2023 by aeh5040

[R0Sch]

12 minutes ago, aeh5040 said:

Impressive work but I don't think this can be quite right. The Earth base with the tilt is not rotationally fixed to the Moon support - it needs to rotate independently. So its rotation needs to be powered by something. The only possibility I can see is that it is fixed to the top of the 28t turntable, presumably by two axles or pins running through the large turntable as I said above. So the tilt base and the small turntable top need to be rotationally aligned.

I agree that the top of the small turntable must be fixed to the bottom of the large one, as you seem to have. But so far as I can see, the pair of them cannot be fixed to the frame - they must be free to rotate, presumably with the red liftarm (or something attached to it) fitting snuggly inside the ring.

Unfortunately we can't compute anything unless we know how the lower axle is geared on the sun side, as I mentioned above.

The Earth base is NOT connected to the Moon support. It just looks like that in the screenshot. But it's free to rotate. You can check out the Studio file I provided. This should make it clearer:

Edited December 6, 2023 by R0Sch

[aeh5040]

2 hours ago, R0Sch said:

The Earth base is NOT connected to the Moon support. It just looks like that in the screenshot. But it's free to rotate. You can check out the Studio file I provided. This should make it clearer:

Ok, I understand, but it needs to be connected to the two turntables.

Like this. The 5L axles go into the black half of the large turntable. (They might be pins rather than axles). Edit: the 28t turntable should be the other way up here.

Edited December 6, 2023 by aeh5040

[pleegwat]

4 hours ago, aeh5040 said:

There is second axle running along the bottom of the arm, which I think drives the 28t turntable in the Earth module, and is doubtless very important for the mechanics.  But where is it geared to in the Sun module?  It is at the level where two vertical 5x7 frames overlap, so there is not much room for gears.  Perhaps there is a 12t bevel (single or double) that meshes with the *underside* of the horizontal 20t double bevel?

The earth rotates around the sun, but the north pole is always pointing toward the pole star, which causes seasons. This means that part of the earth-assembly has to counter-rotate relative to the 'year arm'. I expect the second axle is to transfer this counter-rotation, in which case it is probably linked to a fixed 28t gear on the sun side, and a 28t small turntable on the earth side.

[aeh5040]

19 minutes ago, pleegwat said:

The earth rotates around the sun, but the north pole is always pointing toward the pole star, which causes seasons. This means that part of the earth-assembly has to counter-rotate relative to the 'year arm'. I expect the second axle is to transfer this counter-rotation, in which case it is probably linked to a fixed 28t gear on the sun side, and a 28t small turntable on the earth side.

Yes, I agree that is (hopefully) how it should move. I just cannot see where the axle is connected on the sun side. Where is this fixed 28t gear?

We seem to have a ratio of 3x3x3=27 for moon's orbit to earth's rotation, which is (fairly) good!

Edited December 6, 2023 by aeh5040